Transportation method for a wind turbine blade

ABSTRACT

A method of transporting a wind turbine blade is described, wherein the blade comprises an inner extender section and an outer blade section. The inner extender section is approximately half the length of the outer blade section, and the method comprises securing a pair of inner extender sections together to form an extender transport section, which can be more easily transported as it is approximately the same length as an outer blade section.

FIELD OF THE INVENTION

The present invention relates to a method of transporting a wind turbineblade, in particular a wind turbine blade comprising an inner bladeextender and an outer blade section.

BACKGROUND OF THE INVENTION

As wind turbine sizes increase, it is common for wind turbine to utilisewind turbine blades of considerable length, e.g. blades of 60 metreslength. The transportation of wind turbine blades for such large-scalewind turbines introduces significant logistical problems to theoperation of wind turbine transportation and erection.

Several countries impose length restrictions on transported articles,e.g. requiring that any item over, say, 45 metres long requires anational permit issued by the authorities for road transportation. Theaction of applying for and obtaining such permits can introducesubstantial lead-times relating to blade transportation operations, withsome jurisdictions further imposing time limits for the usage of suchpermits—if a permit is not used within the allotted time limit, e.g. dueto an interruption in the manufacturing process or a delay in apreceding transportation stage, a new permit will then have to beapplied for and issued. Such regulations can introduce additional costsinto the area of wind turbine transportation and installation. As anexample of costs which may be incurred, a delay in the transportation ofwind turbine blades for an offshore wind turbine means that specialisedinstallation equipment for offshore facilities may be required forlonger periods, the hiring costs of which can in some cases beUS$100,000 per day.

Current transportation methods involve providing individualtransportation carriages, e.g. trailers, platforms, rail carriages,etc., for each wind turbine blade. In the case where blades can beprovided as separate blade sections (e.g. as an inner blade extender formounting to a wind turbine rotor hub and an outer blade section formounting to the distal end of the inner blade extender), this results inseveral different transportation vehicles, and acts to increase thetotal transportation requirements and associated costs.

One example is disclosed in patent application WO2006/061806, whichdescribes a method of transporting a plurality of wind turbine rotorblades.

It is an object of the invention to provide a method of transportationfor wind turbine blades which provides for relatively easiertransportation operations combined with reduced spatial requirements.

SUMMARY OF THE INVENTION

Accordingly, there is provided a method of transporting a plurality ofwind turbine rotor blades, said blades having a length of at least 50metres, wherein said blades comprise an inner blade extender and anouter blade section adapted to mount to said inner blade extender,wherein the length of said outer blade section is approximately twicethe length of said inner blade extender, the method comprising the stepof:

-   -   providing at least two of said blades as separate inner blade        extenders and outer blade sections;    -   coupling a first inner blade extender to a second inner blade        extender to form an extender transport section, wherein the        length of said extender transport section is approximately equal        to the length of said outer blade sections; and    -   transporting said extender transport section and said outer        blade sections using a plurality of transport apparatus adapted        to receive blade sections having a length approximately equal to        the length of one of said outer blade sections.

As the inner blade extenders can be coupled together to form anintermediate section suitable for transporting on vehicles arranged totransport outer blade sections, this provides a simplification of theentire transportation operation, reducing the length of the sections tobe transported, as well as requiring less different types of transportvehicles for the sections. Such a system results in reduced logisticsrequirements for the transportation of wind turbine blades, increasedefficiencies, and consequently reduced overall costs.

Preferably, said inner blade extender comprises a root end for mountingto a wind turbine rotor hub and a distal end for coupling to an outerblade section, and wherein said step of coupling comprises coupling oneof said root end or distal end of said first inner blade extender to oneof said root end or distal end of said second inner blade extender.

As the blade extenders are roughly half the length of the outer bladesections, coupling the inner blade extenders to each other at the endsof the blade extenders provides an extender transport section which willbe approximately equal in length to an outer blade section.

Preferably, the method comprises the step of providing a joining partbetween one of said ends of said first inner blade extender and one ofsaid ends of said second inner blade extender, and wherein said step ofcoupling comprises mounting said first inner blade extender and saidsecond inner blade extender to said joining part.

The use of a joining part or coupling device in between the two bladeextenders provides an apparatus to ensure secure mounting between theblade extenders.

Preferably, said step of coupling comprises bolting said first innerblade extender and said second inner blade extender to said joiningpart.

Bolting the blade extenders to the joining part provides a securecoupling method, and allows for the use of existing bolting features ofthe extenders.

Preferably, the joining part comprises bolt circles provided on saidjoining part, said bolt circles corresponding to bolt circles providedat the ends of said first and second inner blade extenders, wherein saidstep of coupling comprises bolting said inner blade extenders to saidjoining part using bolts extending through the bolt circle provided atthe end of inner blade extender, said bolts further extending throughthe bolt circle provided on said joining part.

As the bolt circles of the joining part correspond with and are inregister with the bolt circles of the extenders, this provides a simpleand reliable coupling mechanism between the joining part and theextenders.

Preferably, the bolt circle diameter of the joining part is equal to thebolt circle diameter of an end of said inner blade extender.

As the joining part is configured to correspond to the bolt circlediameter of the blade extender, this allows for the coupling of theextender to the joining part without the need for dedicated joiningapparatus.

In one embodiment, the joining part comprises a first bolt circle havinga first bolt circle diameter corresponding to the bolt circle diameterof the root end of said inner blade extender, the joining part furthercomprising a second bolt circle having a sec- and bolt circle diametercorresponding to the bolt circle diameter of the distal end of saidinner blade extender, wherein said step of coupling comprises boltingthe root end of said first inner blade extender to the first bolt circleof said joining part and bolting the distal end of said second innerblade extender to the second bolt circle of said joining part to formsaid blade extender section.

In this embodiment, the joining part can be arranged such that a distalend of one blade extender can be coupled to the root end of a secondblade extender. To this end, as the root end has a different diameter tothe distal end, consequently the bolt circles have a different diameter,and the joining part is configured accordingly.

Preferably, said rotor blades are partial pitch rotor blades having apitch system provided at the distal end of said inner blade extender,and wherein said step of transporting comprises supporting said extendertransport sections such that said pitch systems are unloaded duringtransportation.

By arranging the transport of the extender transport sections such thatthe pitch systems are unloaded, this means that excessive wear and tearis prevented from affecting the pitch systems and enclosed bearings,e.g. standstill marks in the bearing rings of a pitch system. This canbe particularly useful in situations wherein the extender transportsections are transported or stored for long periods of time.

Preferably, said step of supporting comprises supporting said firstinner blade extender at the centre point of mass of the first innerblade extender and supporting said second inner blade extender at thecentre of mass of the second inner blade extender.

Supporting the sections at the centre of mass of each blade ensures thatthe blades are not being transported in an out-of-balance arrangement,thereby preventing loading and associated wearing on the pitch systemsduring transport.

Preferably, said step of coupling comprises coupling said root end ofsaid first inner blade extender to said root end of said second innerblade extender.

By coupling the root ends of the extender sections together, the pitchsystems are provided at either ends of the extender transport section,and are not impacted on by external loads

Alternatively, said step of coupling comprises coupling said distal endof said first inner blade extender to said distal end of said secondinner blade extender.

In this case, as the pitch systems are provided at the coupling junctionbetween the two extenders, they can be locked into position andprevented from moving during transport.

Preferably, said step of providing comprises providing inner bladeextenders having a length of approximately 20 metres, and outer bladesections having a length of approximately 40 metres.

By providing blade sections of such dimensions, accordingly theresultant outer blade sections and extender transport sections which areto be transported are of a relatively short length, and can relativelyeasily be transported without permit in most jurisdictions.

Preferably, said step of transporting comprises arranging a firstextender transport section adjacent a second extender transport sectionor a first outer blade section on a first transport apparatus.

As the extender transport section is approximately the same length as anouter blade section, this means that extender transport sections andouter blade sections can be transported side-by-side on the sametransport vehicle. This reduces the logistical requirements for thetransportation operation.

In one embodiment, said step of coupling comprises directly mountingsaid first inner blade extender to said second inner blade extender.

It will be understood that the inner blade extenders may be directlymounted to each other, i.e. without the usage of a joining part. Thiscan be facilitated through the identical bolt circles provided on theextenders, which are provided for mounting the extenders to a windturbine rotor hub or to an outer blade section.

It will be understood that said transport apparatus may comprise anysuitable arrangement of road, rail or water vehicles.

DESCRIPTION OF THE INVENTION

Embodiments of the invention will now be described, by way of exampleonly, with reference to the accompanying drawings, in which:

FIG. 1 illustrates a first embodiment of a method for transporting awind turbine blade according to the invention;

FIG. 2 illustrates the transportation of an outer blade sectionapproximately equivalent in length to the extender transport section ofFIG. 1; and

FIG. 3 illustrates a second embodiment of a method for transporting awind turbine blade according to the invention.

With reference to FIGS. 1-2, a method of transporting a wind turbineblade is illustrated. FIG. 1 shows a method for transporting a pair ofinner blade extenders 10 a,10 b for a wind turbine blade. The first andsecond extenders 10 a,10 b are coupled together via a joining piece 12,the joining piece 12 provided between the respective distal ends 11 a,11b of the extenders 10 a,10 b.

The extenders 10 a,10 b comprise a bolt circle arrangement (not shown)provided at the respective distal ends 11 a,11 b for coupling to windturbine components (e.g. an outer blade section). Preferably, thejoining piece 12 comprises a bolt circle defined thereon of equaldimensions to the bolt circles of the extenders 10 a,10 b. Accordingly,joining piece 12 may be arranged such that the bolt circle of thejoining piece is in line with the bolt circle of the distal end 11 a,11b of the extenders 10 a,10 b. The first extender 10 a is then coupled tothe joining piece 12 by bolting the joining piece 12 to the distal end11 a of the extender 10 a via said bolt circles, without the need forspecialist coupling equipment.

Similarly, the second extender 10 b is coupled to the joining piece 12by bolting the joining piece 12 to the distal end 11 b of the extender10 b via the bolt circles provided on the second extender 10 b.

The securing together of the two extenders 10 a,10 b results in thecreation of an intermediate extender transport section, indicatedgenerally at 14.

The extenders 10 a,10 b are arranged such that the length of an extender10 a,10 b is approximately half the length of an associated outer bladesection (16, FIG. 2). Accordingly, the length of the extender transportsection 14 is approximately equal to the length of an associated outerblade section 16.

As the extender transport section 14 and the outer blade section 16 areapproximately the same length, then the extender transport section 14can be transported using the same transport vehicles used to transportthe outer blade sections 16.

In FIGS. 1 and 2, the transport vehicles comprise a truck 18 and aseparate support platform 20, which can be used to carry the extendertransport section 14 and the outer blade section 16. The sections 14,16may be mounted to the transport apparatus 18,20 using any suitable knownconfigurations.

As the sections 14,16 are substantially the same length, it will beunderstood that more than one section 14,16 may be transported on asingle transport apparatus 18,20, e.g. the extender transport section 14of FIG. 1 may be provided adjacent a second extender transport sectionor adjacent an outer blade section. As sections may be transportedside-by-side without significant reconfiguration of the transportapparatus, this can reduce the logistical requirements fortransportation.

For a two-bladed wind turbine, only three separate sections 14,16 needto be transported, i.e. a single extender transport section and twoouter blade sections. These can be transported in any suitableconfiguration, for example a first transport apparatus can carry anextender transport section and at least one of the outer blade sectionsadjacent to the extender transport section. Importantly, the transportapparatus used can be interchangeable, and may be used for either theouter blade sections or the extender transport sections, providing foreconomies of scale in transportation logistics.

This is in contrast to prior art systems, which would requirepotentially four separate transport apparatus (two for the inner bladeextenders and two for the outer blade sections), or at least twodifferently dimensioned transport apparatus (i.e. one apparatus arrangedto receive an inner blade extender and the other arranged to receive anouter blade section).

FIG. 3 illustrates a second embodiment of a method for transporting windturbine blades, in this case transporting a pair of blade extenders 22a,22 b for a partial pitch wind turbine blade. In a partial pitch windturbine, the wind turbine blades comprise an inner blade extender 22a,22 b mounted to a wind turbine rotor hub at the root end 23 a,23 b ofthe extender 22 a,22 b, and an outer blade section 16 mounted to thedistal end 25 a,25 b of the inner blade extender 22 a,22 b, the outerblade section operable to pitch relative to the inner blade extender. Ingeneral, a pitch system 24 is provided at the distal end 25 a,25 b ofthe inner blade extender 22 a,22 b, with the outer blade section 16mounted to said pitch system.

The total partial pitch blade has a length of approximately 60 metres,comprising an inner extender section of approximately 20 metres and anouter blade section of approximately 40 metres. The sections of thepartial pitch blade may be manufactured separately, and transportedindividually to the wind turbine site.

In the embodiment of FIG. 3, similar to the embodiment of FIG. 1, ajoining part 26 is provided between the two extenders 22 a,22 b, but inthis case the root ends 23 a,23 b of the extenders 22 a,22 b are coupledto the joining part 26 to form the extender transport section 28. Suchan arrangement allows for the pitch systems 24 of the extenders 22 a,22b to be positioned at either end of the extender transport section 28,so that the pitch systems 24 are free and unloaded during transport andassociated storage. This results in reduced wear-and-tear on the pitchsystems 24 themselves, particularly with regard to standstill marks inthe pitch system bearings and runways.

As with the embodiment of FIG. 1, the extender transport section 28 ofFIG. 3 is approximately of equivalent length as the associated outerblade sections 16. Accordingly, the extender transport section 28 may betransported in conjunction with outer blade sections 16 in any suitablearrangement, e.g. side-by-side with an adjacent outer blade section 16on a single transport apparatus 18,20.

In a further enhancement of the invention, the extender transportsections 28 may be configured for transport wherein the extenders 22a,22 b are supported such that pitch systems 24 provided at the distalends 25 a,25 b of the extenders 22 a,22 b are unloaded, i.e. are notsubjected to any significant forces during transportation and/orstorage. In this case, the extenders 22 a,22 b may be transported withsupports provided at the centre of mass of the extender sections 22 a,22b, or at the centre of mass of the entire extender transport section 28.Such a support arrangement further reduces the possibility ofsignification wear-and-tear or standstill marks on the pitch systems 24during transportation and associated storage.

It will be understood that while FIGS. 1-3 illustrate a road transportconfiguration of first and second support platforms, the invention mayalso apply for transportation of wind turbine blades by any suitabletransport method, e.g. rail, ocean, etc.

It will also be understood that the inner blade extenders 10 a,10 b,22a,22 b may be transported without the use of joining parts 12,26, i.e.the extenders 10 a,10 b,22 a,22 b may be directly connected to eachother to form the extender transport sections 14,28.

In other embodiments, it may be preferable to couple the distal end of afirst blade extender to the root end of a second blade extender, to forman intermediate extender transport section. In such a case, theassociated joining part may be configured to comprise at least twoseparate bolt circles, a first bolt circle corresponding to the boltcircle diameter of the distal end of said first blade extender and asecond bolt circle corresponding to the bolt circle diameter of the rootend of said second blade extender.

It will be understood that the invention may apply to any wind turbineblade which can be provided as an inner section and an outer section,the inner section approximately half the length of the outer section, toprovide a more efficient and simplified transportation option.

The invention is not limited to the embodiments described herein, andmay be modified or adapted without departing from the scope of thepresent invention.

1. A method of transporting a plurality of wind turbine rotor blades,said blades having a length of at least 50 metres, wherein said bladescomprise an inner blade extender and an outer blade section adapted tomount to said inner blade extender, wherein the length of said outerblade section is approximately twice the length of said inner bladeextender, the method comprising the step of: providing at least two ofsaid blades as separate inner blade extenders and outer blade sections;coupling a first inner blade extender to a second inner blade extenderto form an extender transport section, wherein the length of saidextender transport section is approximately equal to the length of saidouter blade sections; and transporting said extender transport sectionand said outer blade sections using a plurality of transport apparatusadapted to receive blade sections having a length approximately equal tothe length of one of said outer blade sections.
 2. A method as claimedin claim 1, wherein said inner blade extender comprises a root end formounting to a wind turbine rotor hub and a distal end for coupling to anouter blade section, and wherein said step of coupling comprisescoupling one of said root end or distal end of said first inner bladeextender to one of said root end or distal end of said second innerblade extender.
 3. A method as claimed in claim 2, wherein the methodcomprises the step of providing a joining part between one of said endsof said first inner blade extender and one of said ends of said secondinner blade extender, and wherein said step of coupling comprisesmounting said first inner blade extender and said second inner bladeextender to said joining part.
 4. A method as claimed in claim 3,wherein said step of coupling comprises bolting said first inner bladeextender and said second inner blade extender to said joining part.
 5. Amethod as claimed in claim 2, wherein said rotor blades are partialpitch rotor blades having a pitch system provided at the distal end ofsaid inner blade extender, and wherein said step of transportingcomprises supporting said extender transport sections such that saidpitch systems are unloaded during transportation.
 6. A method as claimedin claim 5, wherein said step of supporting comprises supporting saidfirst inner blade extender at the centre point of mass of the firstinner blade extender and supporting said second inner blade extender atthe centre of mass of the second inner blade extender.
 7. A method asclaimed in claim 5, wherein said step of coupling comprises couplingsaid distal end of said first inner blade extender to said distal end ofsaid second inner blade extender.
 8. A method as claimed in claim 1,wherein said step of providing comprises providing inner blade extendershaving a length of approximately 20 metres, and outer blade sectionshaving a length of approximately 40 metres.
 9. A method as claimed inclaim 1, wherein said step of transporting comprises arranging a firstextender transport section adjacent a second extender transport sectionor a first outer blade section on a first transport apparatus.
 10. Amethod as claimed in claim 1, wherein said step of coupling comprisesdirectly mounting said first inner blade extender to said second innerblade extender.